Phenolic constituents,antioxidant and antimicrobial activities of rosy garlic (Allium roseum var. odoratissimum)

The methanol extracts of leaves, flowers, stalks and bulbs of the North African endemic Allium roseum var. odoratissimum were analyzed for their phenolic profiles and screened for their antioxidant and antibacterial activities. Colourimetric analysis revealed that the highest levels of total phenols content (TPC) and total flavonoids content (TFC) were found in the flowers and leaves. The use of HPLC-PDA-MS allowed the identification of kaempferol 3,7-di-O-rhamnoside, kaempferol-3-Glucuronide, kaempferol-3-O-glucoside, kaempferol-3-O-beta-d-glucoside-7-O-alpha-l-rhamnoside, luteoline and apigenine, while four components remained unidentified. The flowers and leaves were found to possess the highest antioxidant activity with the exception in metal chelating ability. Antibacterial assay showed that Enterococcus feacium was the most susceptible bacterial strain and the stalk extract had the most effect in the inactivation of Staphylococcus aureus, Enterococcus feacium, Bacillus subtilis and Escherichia coli. Conclusively, this study allows a clear chemical differentiation between A. roseum var. odoratissimum and the other Allium species.     

Composition of organosulfur compounds from cool- and warm-type garlic (Allium sativum L.) in Korea

The organosulfur and degradation compounds of cool- and warm-type garlic were analyzed in Korea. This garlic exhibited a wide range of organosulfur compound levels. Analytical results indicated large amounts of alliin, γ-glutamyl-S-allyl-l-cysteine (GSAC) and γ-glutamyl-S-trans-1-propenyl-l-cysteine (GSPC) in garlic. The contents of alliin, GSAC, and GSPC were in the range of 10.52–30.12, 11.46–26.45, and 9.15–41.66 mg/g garlic (dry base), respectively. Allicin was the major biological compound at 2.53–9.36mg/g (dry base). GC/MS was employed to identify allicin degradation compounds in fresh garlic. The major chemical components of fresh garlic were diallyl sulfides and methyl allyl sulfides. Differences in the pattern of organosulfur composition and degradation components of thiosulfinates from warm- and cool-type garlic were demonstrated by principle component analysis. Therefore, the results may be useful for the quality evaluation of cool- and warm-type garlic in Korea.     

Biologically active substances in garlic (Allium sativum L.) and their application in nutrition for humans

Reviewed above is chemical composition of garlic and its biological Hypolipidemic, antioxidative, antibacterial and antitumorogenic properties of preparations were elucidated in experimental, clinical and epidemiological observations. It has been concluded that garlic are useful for prevention and combined treatment of most chronical diseases.     

Bioactive compounds,in vitro antioxidant capacity and Maillard reaction products of raw,boiled and fried garlic (Allium sativum L.)

Garlic is used in many dishes but some of its bioactive compounds are lost when exposed to heat. This study evaluated bioactive compounds, antioxidant activity and Maillard reaction products of raw (RG), boiled (BG) and fried garlic (FG). Total phenolic compounds, flavonoids, allicin and phytosterol were quantified as well as dietary fibres and mineral content. Antioxidant activities of RG, BG and FG were evaluated by oxygen radical absorbance capacity (ORAC), oxidation of β‐carotene/linoleic acid and Rancimat methods. The main results were the following: thermal processing of RG decreased both bioactive compounds and antioxidant capacity, boiling was found to be less aggressive than frying, and strong correlations were obtained between total phenolic compounds and the antioxidant assays. However, phytosterol content was higher in FG than in RG and BG and higher temperatures increased the formation of Maillard reaction products. It was concluded that RG and BG should be preferred for human consumption as they present higher antioxidant capacity.     

Influence of sulphate nutrition on the flavour components of garlic (Allium sativum) and wild onion (A. vineale)

Investigation of the relationship between the sulphate nutrition of garlic (Allium sativum) and wild onion(A. vineale) and their flavour strength is now reported. The plants were grown in a glasshouse in sand culture at two concentrations of sulphate in the nutrient medium and their flavour strength determined by sensory, biochemical and gas chromatographic methods. These observations have furnished further examples of environmental control of flavour components. The garlic plants in the two groups differed significantly in their fresh weights per plant. Their sulphur contents also showed that deficiency of this nutrient had been established in spite of the relatively large amount of sulphur introduced in the original cloves. The ratios of total sulphur content in the two groups of plants and of their flavour strengths as determined by total pyruvate values and taste threshold concentrations, respectively, were approximately constant (about 5). Total peak areas in the gas chromatograms increased with increasing (sensory) flavour strength. The garlic plants grown in sand culture were morphologically atypical, possibly because of the high moisture content of the growth medium, but their odour, taste and gas chromatograms were qualitatively indistinguishable from those of field-grown garlic which grew normally. Similar but more pronounced differences of flavour strengths were obtained with A. vineale and in this case the difference in flavour strengths between the deficient and normal plants was about 13-fold. The gas chromatograms of the deficient plants were almost completely lacking in the peaks which are characteristic of Allium sp. The discrepancies between initial and final sulphur contents of the deficient plants are discussed.     

不同溶剂提取对洋葱皮中多酚含量及抗氧化活性的影响

为有效利用废弃的洋葱外皮,以丙酮、甲醇、乙醇和水为溶剂,提取不同品种洋葱皮中的总酚和总黄酮物质,了解他们的含量及抗氧化活性的差异。选用体积分数为70%的丙酮、70%甲醇、70%乙醇和水分别提取红、白、黄3种颜色的洋葱皮,测其表皮中总酚、总黄酮含量。通过测定1,1-二苯基-2-苦肼基(2,2-diphenyl-1-1picrydrazyl,DPPH)自由基清除能力、三价铁还原能力(ferric reducing abilbity of plasma,FRAP)、2,2'-联氨-二-3-基-苯并噻唑-6-磺酸(2,2'-Azinobis-(3-ethylbenzthiazoline-6-sulphonate,ABTS)自由基清除能力,评价其体外抗氧化能力差异。结果显示,紫洋葱皮中抗氧化物质含量和抗氧化能力均显著高于黄、白洋葱皮。70%丙酮提取液中,总酚、总黄酮含量最高,体外抗氧化能力最高,且洋葱皮中总酚对抗氧化能力的贡献高于总黄酮。     

UV-B-induced changes of volatile metabolites and phenolic compounds in blueberries (Vaccinium corymbosum L.)

There are many reports on the potential consequences of UV-B radiation on plants, but there is a rather limited understanding of the effect on secondary plant metabolites, e.g. phenolic compounds and volatiles, at all. The popularity of highbush blueberries (Vaccinium corymbosum L.) is mainly due to its unique flavour and its high content of bioactive compounds, i.e. phenolic compounds. However, information on UV-B elicitor mediated changes on secondary plant metabolites on blueberries is scanty. In the present study, blueberry fruits were harvested and exposed to UV-B radiation with different dosage and adaptation times. With regard to volatile secondary metabolites, C₆-aldehydes, terpenes and ketones, an increase of the relative peak area was observed after both UV-B treatments (0.075 and 0.15 Wh/m² = low [L] and high [H] dosage, respectively). Furthermore, there was a strong influence of the adaptation time. Increasing relative peak areas were determined already after a short adaptation time (2 h) at both, low and high UV-B dosages, but after 24 h adaptation time relative peak areas decreased significantly. However, alcoholic compounds, as degradation products of aldehydes, showed opposite results. In contrast, the non-volatile phenolic compounds revealed a continuously increase with UV-B intensity.     

Garlic (Allium sativum L.): adverse effects and drug interactions in humans

Garlic (Alllium sativum L., Fam Liliaceae) is used medicinally mainly for the treatment of hypercholesterolemia and prevention of arteriosclerosis. Clinical trials have consistently shown that "garlic breath" and body odor are the most common (and well-documented) complaints associated to garlic intake. Case reports have highlighted the possibility that garlic use may cause allergic reactions (allergic contact dermatitis, generalized urticaria, angiedema, pemphigus, anaphylaxis and photoallergy), alteration of platelet function and coagulation (with a possible risk of bleeding), and burns (when fresh garlic is applied on the skin, particularly under occlusive dressings). Consumption of garlic by nursing mothers modifies their infant's behavior during breast-feeding. Finally, garlic may enhance the pharmacological effect of anticoagulants (e. g. warfarin, fluindione) and reduce the efficacy of anti-AIDS drugs (i. e. saquinavir).     

Traditional and modern uses of onion bulb (Allium cepa L.): a systematic review

Abstract

Onion, (Allium cepa L.), is one of the most consumed and grown vegetable crops in the world. Onion bulb, with its characteristic flavor, is the third most essential horticultural spice with a substantial commercial value. Apart from its culinary virtues, A. cepa is also used traditionally for its medicinal virtues in a plethora of indigenous cultures. Several publications have been produced in an endeavor to validate such traditional claims. Nonetheless, there is still a dearth of up-to-date, detailed compilation, and critical analysis of the traditional and ethnopharmacological propensities of A. cepa. The present review, therefore, aims to systematically review published literature on the traditional uses, pharmacological properties, and phytochemical composition of A. cepa. A. cepa was found to possess a panoply of bioactive compounds and numerous pharmacological properties, including antimicrobial, antioxidant, analgesic, anti-inflammatory, anti-diabetic, hypolipidemic, anti-hypertensive, and immunoprotective effects. Although a large number of in vitro and in vivo studies have been conducted, several limitations and research gaps have been identified which need to be addressed in future studies.     

Uptake of arsenic species by turnip (Brassica rapa L.) and lettuce (Lactuca sativa L.) treated with roxarsone and its metabolites in chicken manure

Roxarsone is an organoarsenic feed additive that can be metabolised to other higher toxic arsenic (As) species in animal manure such as arsenate, arsenite, monomethylarsonic acid, dimethylarsinic acid, 3-amino-4-hydroxyphenylarsonic acid and other unknown As species. The accumulation, transport and distribution of As species in turnip (Brassica rapa L.) and lettuce (Lactuca sativa L.) amended with roxarsone and its metabolites in chicken manure were investigated. Results showed arsenite was the predominant As form, followed by arsenate in turnip and lettuce plants, and a low content of dimethylarsinic acid was detected only in lettuce roots. Compared with the control plants treated with chicken manure without roxarsone and its metabolites, the treatments containing roxarsone and its metabolites increased arsenite content by 2.0–3.2% in turnip shoots, by 6.6–6.7% in lettuce shoots, by 11–44% in turnip tubers and by 18–20% in lettuce roots at two growth stages. The enhanced proportion of arsenate content in turnip shoots, turnip tubers and lettuce roots was 4.3–14%, 20–35% and 70%, respectively, while dimethylarsinic acid content in lettuce roots increased 2.4 times. Results showed that the occurrence of dimethylarsinic acid in lettuce roots might be converted from the inorganic As species and the uptake of both inorganic and organic As compounds in turnip and lettuce plants would be enhanced by roxarsone and its metabolites in chicken manure. The pathway of roxarsone metabolites introduced into the human body via roxarsone → animal → manure → soil → crop was indicated.     

Influence of alcoholic fermentation process on antioxidant activity and phenolic levels from mulberries (Morus nigra L.)

The aim of the present study was to evaluate the profile of the phenolic constituents of Morus nigra fruits and their antioxidant activity (DPPH) and to compare their contents before and after fermentation. Antioxidant phenolics of black mulberry (M. nigra L.) samples grown in Galicia (NW Spain) were extracted with methanol/formic acid/water (MFW) and determined by high performance liquid chromatography (HPLC). Two major anthocyanins (cyanidin 3-glucoside and cyanidin 3-rutinoside) and two flavonols (quercetin 3-glucoside and rutin) were isolated, together with caffeic acid and other hydroxycinnamic and ellagic acid derivatives. Their chemical structures were identified by spectral analyses with diode array detection (DAD), but also with alkaline saponification and acid hydrolysis of the mulberry phenolics. Good correlations (r² = 0.6229) were observed among total flavonols contents and the IC₅₀ radical scavenging capacities of mulberry fruits. Anthocyanins are the major flavonoids present in mulberry. It would be expected that anthocyanins contribute significantly to their antioxidant activity; nevertheless, alcohol generated during fermentation may also contribute to antioxidant activity. Our results provide useful antioxidant nutritional information of fresh and fermented mulberry fruits.